Fluid-translating device



H. F. SCHIVIIDT.

FLUID TRANSLATIIIG DEVICE.

APPLICATION FILED SEPT. 14, 19M.

Patented July H I2 0 IN VEN TOR.

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IELUllJ-TBANEELATING DEVICE.

Specification. of Letters Patent.

Application filed September 14 191%. Serial Ito. serene.

To all whom it may concern:

Be it known that I, HENRY F. SCHMIDT, a

citizen of the United States, and a resident,

of Pittsburgh, in the county of Allegheny and State of Pennsylvania,have made a new and. useful Invention in Fluid-Translating Devices, ofwhich the following is a specification; l

This invention relates to fluid translating devices, such, for example,as ejectors, in which the kinetic or velocity energy of the motive fluidis employed in exhausting fluid from a receptacle to be evacuated, or incompressiiig a fluid from a region of lower to a region of lngherpressure.

In e ectors employing dlffusers for bu1ldin u) oressure b7 convertinlrinetic into potential or pressure energy, pulsations in the medium.traversing the diffuser occur to r various reasons. If these pulsationsare of sufficient magnitude thatthe loss occasioned by shock results ina sufficient diminution of the velocity of the medium, and consequentlyof the available kinetic energy, so that the energy is reduced belowthat necessary to overcome the external or discharge pressure, thevelocity in the diffuser will instantly fall to zero. This willreducethe expelling force to zero and consequently occasion a flow in thereverse dircctioiti or from the outlet of the diffuser back into thereg-ion of lower pressure.

AnWobject of this invention is, therefore, to produce an ejectorin whichmeans are employed for preventing pressure oscillations inthediffuser-from becoming large enough to detrimentally affect theoperation ottheejector. i 1 a t A further object of the invention is toproduce a fluid translating device,of the lnnetlc type, inwhich meansare employed for maintalnmg the OPBTZLlJlOIlOf the device substantiallyconstant for practically all varying conditions. j

A still further object is to produce a fluid translating deviceemploying the kinetic or velocity energy, of the motive fluid deliveredto it, in transferring fluid from a region of lower to a region ofhigher pressure, which automatically adjusts itself to variationsin thequantity of fluid conveyed, thus prevent-- ing fluctuations of pressurein; eitherrthe region of higher or lower pressure.

These, and other objects, which will be madeapparentsto those skilled inthe art more or less dia rammatically, a sectional view of an ejectorembodying my invention. The ejector illustrated comprises a suction andcombining chamber 3, which is provided with an inlet port a, a nozzle 5for discharging fluid from a source of fluid pressure through thecombining and suction chamber, and a diffuser 6, which communirates withthe chamber 3 and through which the combined media, issuing from thenozzle 5 and the chamber 3 are discharged to the atmosphere or to aregion of higher pressure with relation to the pressure maintained inthe chamber 3. 'llhe port l is adapted to communicate with the region oflower pressure or with a receptacle to be evacuated.

its illustrated, the diffuser tube terminates in a chamber 7, which, inthe illustrated embodiment, communicates with the atmosphere through aport 8, and incloses a disk 9 capable of closing communication betweenthe outlet of the diffuser and the chamber 7, but which is normally heldin such a po sition, with relation to the outlet of the diffuser, as tooccasion a slight increase in pressure of the media traversing thediffuser at a point immediately adjacent to the diffuser outlet. itsillustrated, the chamber 7 is provided with a wall 10, which forms anannular flange around the outlet of the diffuser 6 and with which thedisk 9 is adapted to cooperate in providing an annular dis chargenozzle, of variable area between the difluser and the chamber 7. Inorder that the disk may move to automatically adjust its position withrelation to the wall 10 to accommodate varying rates of dischargethrough the diffuser 6, l have shown it mounted on a spindle 11, whichis slidably mounted within a bearing l2,mou nted within the chamber 7,and extends axially with relation. to the diffuser. With thisarrangement the disk is not only capable of moving axially with relationto the diffuser, but is prevented from moving laterally. l have alsoshown a coil spring 15, surrounding the spindle l'land operating betweenthe hear ing supporting brackets 18 and the dish, for holding the diskin an operative position retested duly e, men,

with relation to the wall 10. The disk is also provided with a conicaldeflector 14, which extends into the outlet end of the diffuser andoperates to direct the steam from the diffuser into the annular nozzleformed by the cooperation of the disk and the wall 10. This deflector isprovided merely for the purpose of reducing the tendency toward theformation of eddy currents which might result from the sudden change inthe direction of the fluid.

The operation of the apparatus is as follows: The motive fluidtraversing the nozzle 5 is expanded and discharged at a high velocityinto the combining and suction chamber 3, through which it flows inentering the diffuser 6. In traversing the chamber 3, the fluiddischarged from the nozzle 5 entrains the fluid or medium to be ejectedor compressed, and conveys it through the diffuser. As the combinedmedia traverse the diffuser 6, their velocity is decreased, occasioninga conversion from kinetic to potential energy, which appears as anincrease in pressure of the media at the dischargeend of the diffuser,or immediately adjacent to the inlet of the annular nozzle formed by thecooperation of the disk 9 and the wall 10. The combined media intraversing the annular nozzle are locallyv over expanded, between theinlet and outlet of the nozzle,

. thereby occasioning a partial conversion of the potential into kineticenergy. The ratio of the diameter of the mouth of the diffuser 6 to thediameter of the disk 9 is such that an over expansion occurs in theannular nozzle, at some point intermediate the center and the outer edgeof the disk 9, thereby causing the pressure of the media traversing thenozzle to fall below that existing in the chamber 7. By over expansion.is meant an expansion of fluid traversing a nozzle, so that itspressure at some point within confines of the nozzle is below thepressure existing at the outlet of the nozzle, or in the presentexample, below the pressure existing within the chamber 7. It will benoted that the nozzle formed between the disk 9, and the wall 10, may betermed a divergent nozzle, since the fluid passage between the disk andthe plate increases in area from the inlet, near the center of the disk,toward the outlet at the periphery of the disk. As a matter of fact, thenozzle disclosed is a convergent divergent nozzle; the rounded edge ofthe wall 10, at the juncture of that wall with the diffuser 6, forms,with the conical deflector 14, a convergent nozzle, whereas the flatportion of the wall 10 and the disk 9,, form a divergent nozzle.Inasmuch as the pressure difference between the outlet of the diffuser 6and the chamber 7, is less than the reduction in pressure capable ofbeing obtained by employing a converging nozzle, the converging portionof the nozzle illustrated, will first expand the fluid issuing from thediffuser (3. and there-- by cause its pressure to drop. The expansion,due to the velocity thus engendered, will continue in the initialportion of the divergent nozzle, i. 0., the initial portion of thenozzle located between the disk 9 and the wall 10, to such a point, thatover ex iiansion is accomplished. The remaining portion of the divergentnozzle will, acting as a diffuser, re ,*onvert the velocity energy ofthe fluid, re sulting from the expansion, into pressure energy andconsequently build up the pres-are of the fluid as its velocity slowsdown. The disk is further so proportioned with relation to the diameterof'the mouth of the diffuser that the pressure in the chamber T actingon the disk is suflicient to balance the force exerted on the disk bythe combinial media at the mouth of the diffuser. With such anarrangement a desired pressure can be maintained in the chamber 3 and acow dition of equilibrium established in the diffuser G which cannot beupset by variations or fluctuations which may tend to be set up withinthe media traversing the diffuser. This is due to the fact that themedia discharged from the diffuser has a relatively free flow outwardlythrough the annular nozzle, whereas a flow in the reverse direc tion, orfrom the chamber 7 into the diffuser is restricted, since to obtain sucha flow it would be necessary for the pressure on the diffuser side ofthe disk 9 to fall below that in the chamber 7. This would cause thedisk 5) to approach the wall 10 and to restrict the flow from thechamber 7, thereby preventing the formation of harmonic \lln'ations inthe diffuser, since such variations can only exist when the resistanceto their propagation is the same in each direction longitudinally of thevibrations.

The disk 9, therefore, moves to different positions in response to thevariations in flow through the diffuser 6, and, operating as a check toa reverse flow through the diffuser, overcomes the tendency towardupsetting when a minimum amount of. fluid is being ejected from thechamber It will be apparent, to those skilled in the art, that theapparatus shown is merely illustrative, that the nozzle 5 may bereplaced by a series of nozzles, or by a series of nozzles includingaccelerating nozzles operating either in parallel with or in series withthe main expelling nozzles, and that various changes, substitutions.additions or omissions may be made in the apparatus illustrated withoutdeparting from the spirit and scope of the invention as set forth by theappended claims.

What I claim is.

1. In an apparatus of the character described, a diffuser, a chambercommunicating therewith, means for delivering a jet of Lea-aces flu idthrbugh the diffuser for entraining medrum in the chamber, and meanscooperating with the outlet of the diffuser for oc- Ill casioning apartial expansion of the fluid issuing therefrom, and movable inresponse to variations in the partial expansion for varying the outletof the diffuser.

2. In combination with a compressible fluid. ejector, means cooperatingwith the outlet of the ejector for occasioning a partial expansion ofthe fluid issuing from the outlet end of the ejector and movable inresponse to variations in the pressure resulting from said expansion,for controlling the delivery of fluid through the outlet of the ejector.

3. In "combination with a fluid ejector, means cooperating with theoutlet of the ejector for occasioning a local expansion of thefluidissuing from the outlet of the ejector, and movable toward and away fromthe outlet, in response to variations in the local expansion of thefluid.

4t. In combination with an ejector, a disk movably mounted at the outletof the ejector diffuser, and cooperating therewith to form an expansionnozzle for the fluid issuing from the ejector.

5. In combination with an ejector, means cooperating with walls of theejector diffuser outlet for over expanding the fluid issuing from theoutlet, and movable toward and away from the outlet in response tovariations in the expansion occasioned thereby.

6. In combination with an ejector, means for causing a local overexpansion of the fluid issuing from the outlet of the ejector said meansbeing arranged to prevent a reverse flow of fluids so as to dampen theharmonic vibrations tenchng to arise 1n the ejector diffuser due tovariations in the flow of the e ecting and e ected fluids.

7. I11 combination wlth an e ector, a disk I mounted at the outlet ofthe ejector diffuser nozzle for expanding motive fluid and fordelivering it at a high velocity into and through a mixing chamber, amixing chamher, a d ifluser communicating therewith and receiving fluidtherefrom, and an annular nozzle for receiving the combined mediaissuing from the diffuser and located at right angles to the axis of thediffuser.

9. In combination in an ejecting apparatus, a receiving chambercommunicating with'a source of fluid to be ejected, a diffusercommunicating therewith and a nozzle for expanding fluid to the pressurenormally existing in the receiving chamber and for discharging the fluidso expanded into and through said chamber and said diffuser, and anannular passage extending at right angles to the axis of the diffuserand through which. fluid issuing from the diffuser is discharged.

In testimony whereof I have hereunto subscribed my name this 21st day ofAm gust, 191 f.

IIENlt-Y I. SCHMIDT.

Witnesses:

U. I/V. ltfofinnn, IE. W. ltIcCALLIs'ren.

